HMIs can have spectacular graphics. Why shouldn't we use them?

The Abnormal Situation Management Consortium says that people factors account for 42% of incidents, which is why the group spends so much time on operator training and how individuals interface with the control system. (If you’re curious, equipment factors account for 36% of incidents, and process factors for only 22%.)

If an operator has to look at an HMI screen and ask him or herself what that blinking red thing means, it means that the operator is not adequately trained, or that the HMI graphic is not consistent in its use of color. Any time spent gathering thoughts and interpreting graphics simply slows the response and allows the problem to go on longer, potentially escalating in scale and damage. Worse yet, an operator may take the wrong action if he or she doesn't understand immediately what the display is trying to say. Consistency is critical.